Jason Chan thought a man in his restaurant Juno seemed a little suspicious when he entered last Thursday and approached the bar.

When he left, Chan asked a customer there if the man had taken his iPhone; sure enough, it was gone.

Chan remembered the man’s distinctive striped sweater and tracked him down to another nearby restaurant, Lou Malnati’s.

“I tried grabbing him and at that point he basically fought me off and he then tried to leave the restaurant,” Chan tells CBS 2. “We actually broke the door of the restaurant, of Lou Malnati’s, and then he was very adversarial. He tried getting physical with me, and at that point I kind of neutralized him.”